Chap. VI.] ENGINEERING. 467 



])illars were used in pairs, on wliicli beams or slabs were 

 horizontally rested, in order to form a roadway ^, in the 

 same manner that Herodotus describes the most ancient 

 bridge on record, which was constructed by Queen M- 

 tocris, at Babylon ; the planks being laid during the day 

 and hfted again at night, for the security of the city.^ 

 The principle of the arch appears never to have been 

 employed in bridge building. Ferries, and the taxes on 

 crossing by them, are alluded to down to a very late 

 period amongst other sources of revenue.^ 



In forming the bunds of their reservoirs and of the 

 stone dams which they drew across the rivers that were 

 to supply them with water, they were accustomed, with 

 incredible toil, infinitely increased by the imperfection 

 of tools and implements, to work a raised moulding in 

 front of the blocks of stone, so that each course was 

 retained in position, not alone by its own weight, but 

 by the difficulty of forcing it forward by pressure fi-om 

 behind. 



The conduits by which the accumulated waters were 

 distributed, required to be constructed under the bed 

 of the lake, so that the egress should be certain and 

 equal \ as long as any water remained in the tank. 

 To eifect this, they were cut in many instances through 

 sohd granite ; and their ruins present singular ihustra- 

 tions of determined perseverance, undeterred by the 

 most chscouraging difiiculties, and vmreheved by the 

 shghtest apphance of ingenuity to diminish the toil of 

 excavation. 



there is reason to believe tliat the 

 remains of stone piers across the 

 Kalawa-oya, on the line between 

 Kornegalle and Anarajapoora, are the 

 ruins of the bridge erected by King 

 Maha Sen, a.d. 301. 



1 3Iahawanso, ch. Ixxxv. Upham's 

 translation, pp. 340, 349 ; Rqjaratna- 

 cari, pp. 104, 131. The bridge on 

 the Wanny hereafter described (see 

 vol. ii. p. 474) was thus constructed. 



2 Herodotus,!. 186. 



3 3Iahawanso, ch. xxiii. pp. 136, 

 138, ch. XXV. p. 150; Rajaratnacari, 

 p. 112. 



* The Lake of Albano presents an 

 example of a conduit or " emissary" 

 of this peculiar construction to draw 

 off the water. It is upwards of GOOO 

 feet in length. A similar emissary 

 serves a like piu'pose at Lake Nemi. 



